Configuration: OpenCV on Ubuntu, VSCode with code-runner

1. OpenCV installation:

https://opencv.org/get-started/

sudo apt install libopencv-dev

(or install from source:)

cmake -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-4.x/modules -DCMAKE_BUILD_TYPE=Release -DENABLE_CXX11=ON -DWITH_GTK=ON -DWITH_GTK_2_X=ON -DOPENCV_ENABLE_NONFREE=ON -DBUILD_opencv_python2=OFF -DBUILD_opencv_python3=OFF ../opencv-4.x

make -j4

sudo make install

sudo ldconfig

2. VSCode Configuration:

1. ctrl+shift+p   -->   INPUT "c/c++: edit configurations (JSON)"  -->  Click -->   c_cpp_properties.json is generated (in .vscode directory).
2. ctrl+shift+p   -->   INPUT "tasks: configure default build task"  -->  Click  -->  Click "C/C++: g++-7 build active file"(g++, gcc also)  -->  tasks.json is generated (in .vscode directory).
3. In tasks.json, add the last two lines below: 

   			"args": [
   // 				"-std=c++17",
                   "-fdiagnostics-color=always",
                   "-g", "${file}",
                   "-o", "${fileDirname}/${fileBasenameNoExtension}",
                   "-I", "${workspaceFolder}/",
                   "-I", "/usr/local/include/opencv4/",
                   "-L", "/usr/local/lib/libopencv_*",
   //				"-lstdc++fs"
   			],

4. In c_cpp_properties.json, add the last one line below:

               "includePath": [
                   "${workspaceFolder}/**",
                   "/usr/local/include/opencv4"
               ],

3. Code Runner Configuration:

1.  Extensions: install code runner
2. Settings  -->  INPUT: "code runner: executor map"  -->  Edit in settings.json
3. Modify this line:

       "code-runner.executorMap": {
           "cpp": "cd $dir && g++-7 -g $fileName -o $fileNameWithoutExt -I /usr/local/include/opencv4/ -L /usr/local/lib/libopencv_* && $dir$fileNameWithoutExt",

   Insert "-I /usr/local/include/opencv4/ -L /usr/local/lib/libopencv_*" before "&&" (the insertion position is significant);

If cppStandard is c++17, insert "-std=c++17" "-lstdc++fs" as above in 2.3

Check

 Now we can Run Code, or Debug/Run C/C++ File successfully.